Department of Psychiatry, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec.
Can J Psychiatry. 2010 Nov;55(11):715-20. doi: 10.1177/070674371005501105.
The prevalence of pervasive developmental disorders (PDDs) has increased. There has been speculation regarding a role of thimerosal-containing vaccines (TCVs) in this trend. Our objectives were to determine prevalence rates of PDDs among school-aged children, and to evaluate the impact of discontinuation of thimerosal use in 1996 in routine childhood vaccines on PDD rates.
Children (n = 23 635) attending kindergarten to Grade 11 were surveyed in 71 schools from the English Montreal School Board. For children with PDD, information was obtained about their diagnostic subtype, age, sex, grade, and school. Prevalence rates were calculated for the entire school population and for each grade. Prevalence rates were also compared for children born before or after 1996.
Students (n = 187; male to female ratio: 5.4:1) with PDD were identified, corresponding to a prevalence of 79.1/10 000 (95% CI 67.8 to 90.4/10 000). The prevalence was 25.4, 43.6, 9.7, and 0.4 for autistic disorder, PDD not otherwise specified, Asperger syndrome, and childhood disintegrative disorder, respectively. During the study period, there was a significant linear increase in prevalence (OR 1.17 per year; 95% CI 1.12 to 1.23). The trend in prevalence of PDDs was unrelated to the discontinuation of TCVs.
Our study provides additional evidence that the PDD rate is close to 1%. We estimate that at least 11 500 Canadian children aged 2 to 5 years suffer from a PDD. The reasons for the upward trend in prevalence could not be determined with our methods. Discontinuation of thimerosal use in vaccines did not modify the risk of PDD.
广泛性发育障碍（PDD）的患病率有所增加。有人推测含硫柳汞疫苗（TCVs）在这一趋势中起作用。我们的目的是确定学龄儿童中 PDD 的患病率，并评估 1996 年常规儿童疫苗中停止使用硫柳汞对 PDD 发病率的影响。
在英语蒙特利尔学校董事会的 71 所学校中，对幼儿园至 11 年级的儿童进行了调查。对于患有 PDD 的儿童，收集了他们的诊断亚型、年龄、性别、年级和学校等信息。计算了整个学校人群和每个年级的患病率。还比较了出生于 1996 年前或后的儿童的患病率。
共发现 187 名患有 PDD 的学生（男女比例为 5.4:1），患病率为 79.1/10 000（95%CI 67.8 至 90.4/10 000）。分别为自闭症、未特指的 PDD、阿斯伯格综合征和儿童瓦解性障碍，患病率为 25.4、43.6、9.7 和 0.4。在研究期间，患病率呈显著线性上升（每年增加 1.17；95%CI 1.12 至 1.23）。PDD 患病率的趋势与 TCV 停止使用无关。
我们的研究提供了更多证据表明，PDD 率接近 1%。我们估计，加拿大至少有 11500 名 2 至 5 岁的儿童患有 PDD。我们的方法无法确定患病率上升的原因。疫苗中停止使用硫柳汞并未改变 PDD 的风险。
